KR101497756B1 - Impact modifier for metacryl-based resin having excellent impact strength and optical property and method of preparing the same - Google Patents

Abstract

The present invention relates to an impact modifier for methacrylic resin having excellent impact strength and optical properties and a method for producing the same. More specifically, the present invention provides a methacrylic resin impact reinforcing agent for impact resistance, By minimizing the birefringence by providing a difference in refractive index between the seed, the acrylic rubber core and the shell constituting the reinforcing agent, the impact resistance can be improved without lowering the transparency when applied to the methacrylic resin, The effect of metamerism, which is a problem in conventional impact modifiers for transparent resins, can be minimized, and thus the effect of having excellent optical properties can be obtained.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an impact modifier for a methacrylic resin having excellent impact strength and optical properties,

The present invention relates to an impact modifier for a methacrylic resin and a method for producing the same, and more particularly, to an impact modifier for a methacrylic resin, which minimizes birefringence by controlling a refractive index deviation of a seed, an acrylic rubber core, and a shell constituting an impact modifier for a methacrylic resin The impact resistance can be improved without lowering the transparency when applied to a methacrylic resin, and the effect of metamerism, which has been a problem in conventional impact modifiers for transparent resins, can be minimized without using a separate molecular weight modifier To an impact modifier for methacrylic resin, which can provide excellent optical properties together with yellowness, and a method for producing the same.

The methacrylic resin including polymethyl methacrylate (PMMA) resin and the like is excellent in transparency and weather resistance, and is widely used as a substitute for glass because of its excellent hardness, chemical resistance, surface gloss, It is less impact resistance than the material and increases the thickness of the product, or is used only for limited use.

In addition, the conventional impact modifier for transparent resin has a problem of yellowing caused by the effect of metamerism. The metamainism is a phenomenon in which any two colors are well suited to one condition but differ in other conditions In other words, it is most important that the illuminated meta-rhythm occurs in which the two colors match well in one light source, but the other light source causes a wrong phenomenon. This is caused by the fact that the composition of the two color pigments is different from each other, and the wavelengths of the two colors in the visible light region are different from each other.

A method of using the modified methacrylic resin after modifying it with an impact modifier to improve transparency while improving the impact resistance of the double methacrylic resin has been proposed. For example, in Korean Patent Laid-Open No. 10-2009-0074979, it is mentioned that the refractive index is 1.48 to 1.50 and the refractive index of the seed is preferably equal to maintain the transparency of the core. However, there is no mention of the color characteristic (yellowness) due to the effect of meta-neuron, and there is a disadvantage in that the haze value does not show excellent characteristics.

In addition, Korean Patent Laid-Open No. 10-2010-0095788 discloses that the index of refraction of the seed, core and crosslinked cell of the impact modifier is 1.48 to 1.50 in order to be similar to the refractive index of the matrix, Can be found. However, it was confirmed that the optical characteristics were somewhat lowered.

Further, in Korean Patent Laid-Open No. 10-2010-0050874, the description of the invention explains that the monomer used in the production of the rubbery polymer controls the composition ratio of the monomer so as to maintain the same refractive index as that of the methacrylic resin. , It is preferable to adjust the refractive index in the range of 1.4 to 1.6, more preferably 1.45 to 1.55, and even more preferably 1.485 to 1.4905 based on the refractive index 1.49 of the polymethyl methacrylate resin.

However, the above-described refractive index control ranges are not only so wide as to maintain the same refractive index, but also have a problem in that they show very large differences in terms of optical characteristics and impact strength.

In addition, Korean Patent Laid-Open Nos. 10-2010-0050874 and 4,999,402 mentioned above disclose a method for improving workability by adding a molecular weight modifier for the purpose of preventing deterioration of mechanical properties, And the disadvantage that the characteristics are somewhat deteriorated can be confirmed.

It is an object of the present invention to solve the above problems of the prior art, and it is an object of the present invention to provide an impact modifier for a methacrylic resin, which is capable of minimizing birefringence by controlling a refractive index deviation of a seed, an acrylic rubber core, It is possible to improve the impact strength without lowering the transparency when applied and minimize the effect of metamerism which is a problem in conventional impact modifiers for transparent resins without using a separate molecular weight modifier, ) Provides an excellent optical property, and also provides a method of manufacturing the impact modifier for methacrylic resin.

In order to accomplish the object of the present invention, according to the present invention, there is provided an impact modifier for methacrylic resin comprising a seed, an acrylic rubber core and a shell,

5 to 30% by weight of the seed, 50 to 60% by weight of the acrylic rubber core, and 15 to 25% by weight of the shell,

Wherein the refractive index difference between the seed and the acrylic rubber core and the difference between the refractive index of the acrylic rubber core and the shell are in the range of 0.001 to 0.03 within the range of 1.48 to 1.49, An impact modifier for methacrylic resin is provided.

Further, according to the present invention,

(a) preparing a seed formed by emulsion polymerization of a monomer mixture comprising an alkyl methacrylate monomer having an alkyl group having 2 to 8 carbon atoms, an alkyl acrylate monomer having an alkyl group having 1 to 8 carbon atoms, and a crosslinkable monomer; step;

(b) preparing an acrylic rubber core surrounding the seed and emulsion-polymerized with at least one monomer mixture selected from the group consisting of an aromatic vinyl monomer and a crosslinkable monomer, with an alkyl acrylate monomer having 1 to 8 carbon atoms; And

(c) a step of wrapping the core and emulsion-polymerizing a mixture of at least one monomer selected from the group consisting of an alkyl acrylate monomer having an alkyl group having 1 to 8 carbon atoms and an aromatic vinyl monomer in a methyl methacrylate monomer; Respectively,

Wherein the refractive index of the acrylic rubber core (b) and the deviation between the refractive index of the methacrylic resin as the target resin of the impact modifier satisfy the range of 0.004 to 0.0002. The method of manufacturing an impact modifier for a methacrylic resin according to claim 1, to provide.

Further, according to the present invention, the residual methacrylic resin is added to 10 to 30% by weight of the impact modifier for methacrylic resin,

The impact modifier for a methacrylic resin is characterized in that the difference between the refractive index of the acrylic rubber core in the impact modifier and the refractive index of the methacrylic resin is in the range of 0.004 to 0.0002, Wherein the difference in refractive index between the seed and the acrylic rubber core and the difference between the refractive index of the acrylic rubber core and the shell are in the range of 0.001 to 0.03, respectively, in the range of 1.48 to 1.49.

Hereinafter, the present invention will be described in detail.

Specifically, the present invention has technical features as an impact modifier for a transparent resin, which maintains excellent transparency and impact strength, minimizes the refractive index adjustment and meta heading between layers, and provides a color similar to a matrix resin.

This technical feature is an impact modifier for a methacrylic resin comprising a seed, an acrylic rubber core and a shell, wherein the seed is 5 to 30 wt%, the acrylic rubber core is 50 to 60 wt%, and the shell is 15 to 25 wt% Wherein the refractive index difference between the seed and the acrylic rubber core and the refractive index difference between the acrylic rubber core and the shell are in the range of 0.001 to 0.03 in the range of 1.48 to 1.49, Can be achieved by satisfaction.

In particular, as described in the following examples, it is preferable that the refractive index of the seed is smaller than the refractive index of the acrylic rubber core by 0.001 to 0.03, and the refractive index of the shell is larger than the refractive index of the shell by 0.001 to 0.03. This is because the effect of metamerism, which is a problem in the impact modifier for transparent resin, can be minimized, and thus the optical characteristics of yellow color can be imparted.

The refractive index of the acrylic rubber core is not particularly limited as long as it is within the range of 1.48 to 1.49, but it is preferable that the refractive index of the seed and the shell is suitably adjusted to satisfy the range of 1.4878 to 1.4889, Do.

In particular, in the present invention, the deviation between the refractive index of the acrylic rubber core and the refractive index of the methacrylic resin is preferably in the range of 0.004 to 0.0002, more preferably in the range of 0.002 to 0.0011, This is because the impact strength can be improved without lowering the transparency of the methacrylic resin composition within the above range.

In the present invention, the term "seed" as used herein means an amount of 5 to 99 parts by weight of an alkyl methacrylate monomer having an alkyl group having 2 to 8 carbon atoms, based on 100 parts by weight of the total monomers constituting the impact modifier, an alkyl acrylate having an alkyl group having 1 to 8 carbon atoms 0.5 to 90 parts by weight of a monomer derived from an unsaturated monomer, and 0.5 to 5 parts by weight of a crosslinkable monomer is formed by emulsion polymerization and has an average particle diameter of 170 to 220 nm.

When the average particle size of the prepared seeds is less than 170 nm, there is a problem that the impact strength is lowered. When the average particle diameter of the seeds is less than 170 nm, there is a problem that the transparency Which is not preferable.

Examples of the alkyl methacrylate having an alkyl group having 2 to 8 carbon atoms include ethyl methacrylate, propyl methacrylate, isopropyl methacrylate, butyl methacrylate, hexyl methacrylate, octyl methacrylate, and 2-ethyl Hexyl methacrylate, and hexyl methacrylate.

Examples of the alkyl acrylate having an alkyl group having 1 to 8 carbon atoms include methyl acrylate, ethyl acrylate, propyl acrylate, isopropyl acrylate, butyl acrylate, hexyl acrylate, octyl acrylate, and 2-ethylhexyl acrylate Or a combination thereof.

The crosslinkable monomer may be selected from the group consisting of 1,3-butanediol diacrylate, 1,3-butanediol dimethacrylate, 1,4-butanediol diacrylate, 1,4-butanediol dimethacrylate, Alkyl acrylate having an alkyl group, alkyl methacrylate having an alkyl group, allyl methacrylate, trimethylolpropane triacrylate, tetraethylene glycol diacrylate, tetraethylene glycol dimethacrylate, divinylbenzene, polyethylene glycol acrylate, polyethylene glycol methacrylate, And polyethylene glycol diacrylate.

If the amount of the seed is less than 5% by weight, a sufficient impact strength can not be exhibited due to a small final particle size depending on the seed particle size. When the amount of the seed is more than 30% by weight, There is a problem that the particle diameter becomes too large and sufficient transparency can not be exhibited.

Also, in the present invention, the acrylic rubber core comprises, in the presence of the seed, 50 to 99 parts by weight of an alkyl acrylate monomer having an alkyl group having 1 to 8 carbon atoms based on 100 parts by weight of the total monomers constituting the impact modifier, 0 to 40 parts by weight of a crosslinking monomer and 0.5 to 5 parts by weight of a crosslinking monomer are emulsion-polymerized to enclose the seed and have an average particle diameter within a range of 240 to 300 nm.

When the average particle diameter is less than 240 nm, the impact strength is lowered. When the average particle diameter exceeds 300 nm, the transparency is rapidly decreased.

The aromatic vinyl monomer may be at least one selected from the group consisting of styrene,? -Methylstyrene, p-methylstyrene, vinyltoluene, alkylstyrene substituted with an alkyl group having 1 to 3 carbon atoms, and styrene substituted with a halogen .

The alkyl acrylate monomer having an alkyl group having 1 to 8 carbon atoms and the crosslinkable monomer may be of the kinds described in the production of the seed.

If the content of the acrylic rubber core is less than 50% by weight, the particle size of the final particles may be small due to the particle size of the core, so that sufficient impact strength can not be exhibited. If the content of the acrylic rubber core exceeds 60% The particle size of the final particles becomes too large to achieve sufficient transparency.

In the present invention, in the present invention, in the presence of the core, the shell may contain, based on 100 parts by weight of the total monomers constituting the impact modifier, 50 to 99.995 parts by weight of a methyl methacrylate monomer, an alkyl acrylate monomer having an alkyl group having 1 to 8 carbon atoms And 0.005 to 50 parts by weight of a monomer selected from the group consisting of an aromatic vinyl monomer and an aromatic vinyl monomer is emulsion-polymerized to enclose the core and have an average particle size within the range of 260 to 340 nm.

When the average particle diameter is less than 260 nm, there is a problem that the impact strength is lowered, and when the average particle diameter is more than 340 nm, transparency is rapidly lowered.

The alkyl acrylate monomer having an alkyl group having 1 to 8 carbon atoms and the aromatic vinyl monomer may be of the types described in the production of the acrylic rubber core.

If the amount of the shell is less than 15% by weight, the particle size of the final particles is too small to exhibit a sufficient impact strength. When the amount of the shell is more than 50% by weight, The particle size of the particles becomes too large and sufficient transparency can not be exhibited.

These impact modifiers for methacrylic resins can be prepared in the following manner:

That is, (a) an alkyl methacrylate monomer having an alkyl group having 2 to 8 carbon atoms, an alkyl acrylate monomer having an alkyl group having 1 to 8 carbon atoms, and a monomer mixture comprising a crosslinkable monomer are formed by emulsion polymerization Seed preparation step;

(b) preparing an acrylic rubber core surrounding the seed and emulsion-polymerized with at least one monomer mixture selected from the group consisting of an aromatic vinyl monomer and a crosslinkable monomer, with an alkyl acrylate monomer having 1 to 8 carbon atoms; And

(c) a step of wrapping the core and emulsion-polymerizing a mixture of at least one monomer selected from the group consisting of an alkyl acrylate monomer having an alkyl group having 1 to 8 carbon atoms and an aromatic vinyl monomer in a methyl methacrylate monomer; As shown in FIG.

As described above, it is preferable that the refractive index of the acrylic rubber core (b) and the deviation between the refractive index of the methacrylic resin as the target resin of the impact modifier satisfy the range of 0.004 to 0.0002.

It is also preferable that the refractive index difference between the seed and the acrylic rubber core and the refractive index difference between the acrylic rubber core and the shell are in the range of 0.001 to 0.03 in the range of the refractive index of the seed, the acrylic rubber core and the shell within the range of 1.48 to 1.49 . More specifically, the refractive index of the seed is smaller than the refractive index of the acrylic rubber core by 0.001 to 0.03, and the refractive index of the shell is preferably larger than the refractive index of the shell by 0.001 to 0.03.

At this time, the refractive index of the acrylic rubber core is not particularly limited, but it is most preferably in the range of 1.4878 to 1.4889.

In the present invention, the impact modifier for methacrylic resin is composed of 10 to 30% by weight of an impact modifier for methacrylic resin and 70 to 90% by weight of a methacrylic resin, wherein the refractive index of the acrylic rubber core in the impact modifier And the index of refraction of the methacrylic resin within the range of 0.004 to 0.0002, and the index of refraction of the seeds of the impact modifier and the acrylic rubber core and the shell is in the range of 1.48 to 1.49, and the refractive index difference between the seed and the acrylic rubber core , And a difference in refractive index between the acrylic rubber core and the shell is in the range of 0.001 to 0.03, respectively.

The resin composition may further contain additives such as dyes, pigments, lubricants, antioxidants, ultraviolet stabilizers, heat stabilizers, reinforcing agents, fillers, and light stabilizers which are conventionally used depending on the application.

According to the present invention, the birefringence is minimized by providing the refractive index difference between the seed, the acrylic rubber core and the shell instead of the same interlayer refractive index as that of the impact modifier for transparent resin in the prior art, so that transparency does not decrease when applied to a methacrylic resin It is possible to improve the impact strength and to have an optical property with excellent yellowness by minimizing the effect of metamerism which is a problem in conventional impact modifiers for transparent resins without using a separate molecular weight modifier Can be obtained.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the invention as set forth in the appended claims. Changes and modifications may fall within the scope of the appended claims.

[ Example ]

Example  One

(a) Preparation of seed

80 parts by weight of ion-exchanged water was charged into a 3 L glass reactor and the temperature was raised to 70 DEG C with nitrogen washing. When the temperature of the ion exchange water reached 70 ° C, 0.04 parts by weight of sodium dodecyl sulfate (SLS, 3 wt% solution), 4.44 parts by weight of methyl methacrylate (MMA), 0.54 parts by weight of butyl acrylate (BA) 0.02 parts by weight of methacrylate (AMA) were simultaneously added thereto.

When the temperature in the reactor was stabilized at 70 캜, 0.08 parts by weight of potassium persulfate (KPS, 3 wt% solution) was added to initiate polymerization. After aging for 1 hour, 0.09 parts by weight of sodium dodecyl sulfate (SLS, 3 wt% solution), 13.32 parts by weight of methyl methacrylate (MMA), 1.62 parts by weight of butyl acrylate (BA) AMA) were stirred to emulsify the monomers.

The emulsified monomer was dropped into the reactor at a temperature of 70 캜 for 1.5 hours in a nitrogen atmosphere, and 0.0094 part by weight of ethylenediaminetetra sodium acetate, 0.006 part by weight of ferrous sulfate, 0.04 part by weight of sodium formaldehyde sulfoxylate, 0.03 part by weight of diisopropylbenzene hydroperoxide (DIPHP, 54 wt.% Solution) was added thereto. After completion of the reaction, aging was carried out for 1 hour, and the nitrogen washing was carried out continuously until the reaction was terminated.

At this time, the seed was 20% by weight based on 100% by weight of total monomers constituting the impact modifier of the present invention.

The average particle diameter of the polymerized seed latex was measured using a laser light scattering apparatus NICOMP to obtain a thin film having a thickness of 180 nm and a resin having a thickness of 2 mm and then measuring the refractive index measured using an Abbe refractometer at 25 ° C according to ASTM D1298 Was 1.4875.

(b) Production of acrylic rubber core

First, 25 parts by weight of ion-exchanged water, 0.4 parts by weight of sodium dodecyl sulfate, 44.5 parts by weight of butyl acrylate, 9.5 parts by weight of styrene, 0.5 parts by weight of allyl methacrylate and 0.5 parts by weight of polyethylene glycol diacrylate (PEGDA) The monomers were emulsified.

After completion of the seed polymerization, the emulsified monomer was dropped to the reactor containing 20% by weight of the total monomers in an amount of 100% by weight of the total monomers at 70 DEG C under a nitrogen atmosphere for 2 hours, and 0.0235 part by weight of ethylenediaminetetra sodium acetate, 0.015 part by weight of ferrous sulfate, 0.1 part by weight of sodium formaldehyde sulfoxylate, and 0.2 part by weight of diisopropylbenzene hydroperoxide were added thereto, followed by aging for 1 hour after completion of the reaction.

At this time, the acrylic rubber core was in a proportion of 55% by weight based on 100% by weight of the total monomers constituting the impact modifier of the present invention. The conversion of the polymerized core latex was 98%, the average particle diameter was 280 nm, and the refractive index was 1.4883.

(c) Shell manufacture

12 parts by weight of ion-exchanged water, 0.2 part by weight of sodium dodecyl sulfate, 24.4 parts by weight of methyl methacrylate and 0.6 part by weight of methyl acrylate were emulsified and then added dropwise to the reactor in which the core polymerization was completed for 1 hour. At this time, the core content in the reactor corresponds to a ratio of 55% by weight based on 100% by weight of the total monomers constituting the impact modifier.

0.00235 parts by weight of ethylenediaminetetra sodium acetate, 0.0015 part by weight of ferrous sulfate, 0.01 part by weight of sodium formaldehyde sulfoxylate, and 0.02 part by weight of diisopropylbenzene hydroperoxide were added, and the mixture was allowed to stand for 1 hour And aged, and washed successively with nitrogen until the reaction was complete.

At this time, the cell ratio was 25% by weight based on 100% by weight of the total monomers constituting the impact modifier of the present invention. The conversion of the finally polymerized transparent resin latex was 99%, the average particle size was 300 nm, and the refractive index was 1.4898.

≪ Production of transparent resin composition >

Ion exchange water was added to the final transparent resin latex prepared as described above to lower the final solids content to 15% by weight or less, and then the temperature was raised to 80 ° C with stirring with a stirrer. A calcium chloride aqueous solution having a concentration of 22 wt% was added thereto to prepare a mixture in the form of a slurry. The mixture was heated to 90 DEG C or higher and aged, followed by cooling. The cooled mixture was washed with ion-exchanged water, filtered, and dried to obtain a powdery transparent resin.

To 100 parts by weight of a mixture of 20 parts by weight of the powdery transparent resin obtained and 80 parts by weight of polymethylmethacrylate, 0.2 part by weight of the lubricant, 0.1 part by weight of the antioxidant and 0.01 part by weight of the light stabilizer were added and kneaded, To prepare a pellet, and the pellet was again injected to prepare a specimen.

Table 1 summarizes the composition, refractive index and final particle diameter of the above-mentioned impact modifier and resin composition, and the total light transmittance, haze, and yellowness as optical characteristics are measured in addition to the impact strength, and the measurement results are summarized in Table 1 .

Example  2

The same experiment as in Example 1 was repeated except that the butyl acrylate content was changed to 44.7 parts by weight and the styrene content was changed to 9.3 parts by weight in the preparation of the acrylic rubber core (b) in Example 1 to prepare a test piece , The total light transmittance, the haze and the yellowness as optical characteristics were measured, and the measurement results are summarized in Table 1 below.

Example  3

The same experiment as in Example 1 was repeated except that the butyl acrylate content was changed to 44.57 parts by weight and the styrene content was changed to 9.43 parts by weight in the preparation of the acrylic rubber core (b) in Example 1, In addition to the impact strength, the total light transmittance, haze, and yellowness were measured as optical characteristics, and the measurement results are summarized in Table 1 below.

Example  4

The same tests as in Example 1 were repeated except that the butyl acrylate content was changed to 44.4 parts by weight and the styrene content was changed to 9.6 parts by weight in the preparation of the acrylic rubber core (b) in Example 1, In addition to the impact strength, the total light transmittance, haze, and yellowness were measured as optical characteristics, and the measurement results are summarized in Table 1 below.

Example  5

The same tests as in Example 1 were repeated except that the butyl acrylate content was changed to 44.2 parts by weight and the styrene content was changed to 9.8 parts by weight in the preparation of the acrylic rubber core (b) in Example 1, In addition to the impact strength, the total light transmittance, haze, and yellowness were measured as optical characteristics, and the measurement results are summarized in Table 1 below.

Comparative Example  One

(B) 43.75 parts by weight of butyl acrylate and 10.25 parts by weight of styrene in the preparation of the acrylic rubber core (b), (c) 24.9 parts by weight of methyl methacrylate, 0.1 part by weight, and the total light transmittance, haze and yellowness were measured as optical characteristics in addition to the impact strength, and the measurement results are shown in Table 1 below Together.

Comparative Example  2

(Meth) acrylate (MMA) in an amount of 4.96 parts by weight and a butyl acrylate (BA) content in an amount of 0.02 parts by weight in the preparation of the seeds of Example 1 (a) The same experiment as in Example 1 was repeated except that the rate was changed to 24.9 parts by weight and methyl acrylate was changed to 0.1 part by weight, and the total light transmittance, haze, and yellowness were measured as optical characteristics along with the impact strength The following measurement results are summarized together in Table 1 below.

Comparative Example  3

(Meth) acrylate (MMA) content of 4.96 parts by weight and butyl acrylate (BA) content of 0.02 parts by weight in the preparation of (a) seeds in Example 1, Except that the acrylate content was changed to 43.75 parts by weight and the styrene content was changed to 10.25 parts by weight, the same experiment as in Example 1 was repeated to prepare specimens. In addition to the impact strength, the total light transmittance, haze, And the measurement results are summarized together in Table 1 below.

Comparative Example  4

(Meth) acrylate (MMA) content of 4.96 parts by weight and butyl acrylate (BA) content of 0.02 parts by weight in the preparation of (a) seeds in Example 1, Except that the acrylate content was changed to 43.75 parts by weight and the styrene content was changed to 10.25 parts by weight and (c) 24.9 parts by weight of methyl methacrylate and 0.1 part by weight of methyl acrylate were used in the preparation of the shell. The same experiment was repeated to prepare specimens. Total light transmittance, haze, and yellowness were measured as optical properties along with the impact strength, and the measurement results are summarized together in Table 1 below.

Comparative Example  5

100% by weight of a polymethylmethacrylate resin (LG-MMA, IH830A) was extruded and extruded at an extrusion temperature of 240 DEG C to prepare a physical specimen, and the total light transmittance, haze, and yellowness The measurement results are summarized together in Table 1 below.

Comparative Example  6

The same procedure as in Example 1 was repeated except that 0.1 part by weight of dodecyl mercaptan (TDDM), which is a molecular weight modifier, was added only to the shell polymerization step (c) in Example 1, The transmittance, haze, and yellowness of the total light were measured as characteristics, and the measurement results are summarized together in Table 1 below.

<Conditions for measuring physical properties>

It was measured according to ASTM D1003 using an injection molded plaque having a thickness of 3.175mm: 1) total light transmittance (%) and haze (Haze,%).

2) Impact strength ( kgf · m / m) : Izod impact strength was measured at 23 ° C. in accordance with ASTM D256 using 1/8 "(thickness 3.175 mm) specimen.

3) Yellowness degree: Measured according to ASTM D1925 using a molded plate having an injection angle of 3.175 mm.

4) meth head algorithms (metarism) Measurement: HDT injection was visually measure the color with the HDT specimens that can be obtained from the leg plate molded article was determined based on the 5-point method in accordance with the front and the color difference and the yellowing of the side Fig.

division Example 1 Example 2 Example 3 Example 4 Example 5 Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5 Comparative Example 6 Composition of impact modifier Seed 20 20 20 20 20 20 20 20 20 - 20 core 55 55 55 55 55 55 55 55 55 - 55 Shell 25 25 25 25 25 25 25 25 25 - 25 final
Particle size 3000 3000 3000 3000 3000 3000 3000 3000 3000 - 3000 Seed refractive index 1.4875 1.4875 1.4875 1.4875 1.4875 1.4875 1.4900 1.4900 1.4900 - 1.4875 Core refractive index 1.4883 1.4878 1.4881 1.4885 1.4889 1.4900 1.4883 1.4900 1.4900 - 1.4883 Shell refractive index 1.4898 1.4898 1.4898 1.4898 1.4898 1.4900 1.4900 1.4898 1.4900 - 1.4898 Compound composition Impact modifier 20 20 20 20 20 20 20 20 20 - 20 PMMA (IH830A) 80 80 80 80 80 80 80 80 80 100 80 Impact strength (kgf.m / m) 5.0 4.9 4.8 4.7 4.6 3.9 3.8 3.6 3.0 1.8 4.3 Optical characteristic Total light transmittance (%) 93.7 93.7 93.6 93.5 93.5 93.4 93.5 93.0 93.5 94.0 93.7 Haze (%) 0.9 1.0 1.2 1.1 1.2 1.6 1.8 1.6 1.0 0.5 0.9 Yellowness 0.7 0.9 0.8 0.9 1.3 1.9 2.0 2.0 1.3 0.5 0.8 Visual color measurement (based on 5 points) 5.0 4.5 4.5 4.0 3.5 3.5 3.5 3.5 4.5 5.0 4.5

As shown in Table 1, in the case of Examples 1 to 5 in which the refractive index of the acrylic rubber core and the deviation between the refractive index of the methacrylic resin as the object resin for the impact modifier were finely maintained in an appropriate range while realizing the inter- Example 5 The impact strength was increased by 3 times, and transparency was maintained, and no significant difference was observed in the measured value of the yellowing degree or the naked eye color.

Further, in the case of Comparative Examples 1-4, although the adjustment of the refractive index for each step and the entire step were the same as that of the matrix resin, rather than finely adjusting the deviation between the refractive indexes to an appropriate range, And it was confirmed that it showed good results.

Further, in Comparative Example 5 in which a molecular weight modifier was added, it was confirmed that there was little difference in transparency when compared with the result of Example 1, but the visual color and the impact strength were lowered.

Further, as a result of the measurement of the metamerism, it was not possible to find a difference in the meta-rhythm according to the angle in the case of the embodiment 1, and in the case of the embodiment 2-4, , But we could observe that meta - rhinomas occurred at some angles.

Considering that the metamerism is minimized, it is further confirmed that the embodiment 1 is more preferable than the embodiment 2-4.

Claims (15)

In an impact modifier for methacrylic resin comprising a seed, an acrylic rubber core, and a shell,
20 to 30% by weight of the seed, 50 to 60% by weight of the acrylic rubber core, and 15 to 25% by weight of the shell,
Wherein the refractive index difference between the seed and the acrylic rubber core and the difference between the refractive index of the acrylic rubber core and the shell are in the range of 0.001 to 0.03 within the range of 1.48 to 1.49, Impact modifier for methacrylic resin.
The method according to claim 1,
Wherein the index of refraction of the seed is smaller than the refractive index of the acrylic rubber core by 0.001 to 0.03 and the index of refraction of the shell is larger by 0.001 to 0.03 than the index of refraction of the shell.
3. The method of claim 2,
Wherein the refractive index of the acrylic rubber core is in the range of 1.4878 to 1.4889.
The method according to claim 1,
Wherein the difference between the refractive index of the acrylic rubber core and the refractive index of the methacrylic resin is in the range of 0.004 to 0.0002.
5. The method of claim 4,
Wherein the difference between the refractive index of the acrylic rubber core and the refractive index of the methacrylic resin is in the range of 0.002 to 0.0011.
The method according to claim 1,
The seed is preferably used in an amount of 5 to 99 parts by weight, based on 100 parts by weight of total monomers constituting the impact modifier, an alkyl methacrylate monomer having an alkyl group having 2 to 8 carbon atoms, an alkyl acrylate monomer having an alkyl group having 1 to 8 carbon atoms 0.5 to 90 parts by weight of a crosslinking monomer, and 0.5 to 5 parts by weight of a crosslinking monomer is formed by emulsion polymerization and has an average particle diameter of 170 to 220 nm.
The method according to claim 1,
Wherein the acrylic rubber core comprises 50 to 99 parts by weight of an alkyl acrylate monomer having an alkyl group having 1 to 8 carbon atoms and 0 to 40 parts by weight of an aromatic vinyl monomer based on 100 parts by weight of the total monomers constituting the impact modifier, And 0.5 to 5 parts by weight of a crosslinking monomer is emulsion-polymerized to encapsulate the seed, and has an average particle diameter within a range of 240 to 300 nm. The impact modifier for methacrylic resin according to claim 1,
The method according to claim 1,
Wherein the shell comprises, in the presence of the core, from 50 to 99.995 parts by weight of a methyl methacrylate monomer, an alkyl acrylate monomer having an alkyl group having 1 to 8 carbon atoms and an aromatic vinyl monomer having an alkyl group of 1 to 8 carbon atoms, based on 100 parts by weight of the total monomers constituting the impact modifier , And 0.005 to 50 parts by weight of a monomer selected from the group consisting of the above-mentioned monomers is emulsion-polymerized to surround the core and have an average particle diameter within the range of 260 to 340 nm.
8. The method according to claim 6 or 7,
The crosslinkable monomer may be selected from the group consisting of 1,3-butanediol diacrylate, 1,3-butanediol dimethacrylate, 1,4-butanediol diacrylate, 1,4-butanediol dimethacrylate, Alkyl acrylate having an alkyl group, alkyl methacrylate having an alkyl group, allyl methacrylate, trimethylolpropane triacrylate, tetraethylene glycol diacrylate, tetraethylene glycol dimethacrylate, divinylbenzene, polyethylene glycol acrylate, polyethylene glycol methacrylate, And polyethylene glycol diacrylate. The impact modifier for methacrylic resin according to claim 1,
9. The method according to claim 7 or 8,
Wherein the aromatic vinyl monomer is at least one member selected from the group consisting of styrene,? -Methylstyrene, p-methylstyrene, vinyltoluene, alkylstyrene substituted with alkyl groups having 1 to 3 carbon atoms and halogen substituted with halogen Impact modifier for methacrylic resin.
(a) preparing a seed formed by emulsion polymerization of a monomer mixture comprising an alkyl methacrylate monomer having an alkyl group having 2 to 8 carbon atoms, an alkyl acrylate monomer having an alkyl group having 1 to 8 carbon atoms, and a crosslinkable monomer; step;
(b) preparing an acrylic rubber core surrounding the seed and emulsion-polymerized with at least one monomer mixture selected from the group consisting of an aromatic vinyl monomer and a crosslinkable monomer, with an alkyl acrylate monomer having 1 to 8 carbon atoms; And
(c) a step of wrapping the core and emulsion-polymerizing a mixture of at least one monomer selected from the group consisting of an alkyl acrylate monomer having an alkyl group having 1 to 8 carbon atoms and an aromatic vinyl monomer in a methyl methacrylate monomer; Respectively,
Wherein the refractive index of the acrylic rubber core (b) and the deviation between the refractive index of the methacrylic resin as the target resin of the impact modifier are within the range of 0.004 to 0.0002.
12. The method of claim 11,
Wherein the refractive index difference between the seed and the acrylic rubber core and the difference between the refractive index of the acrylic rubber core and the shell are in the range of 0.001 to 0.03 within the range of 1.48 to 1.49, METHOD FOR PRODUCING IMPACT ARTICULATOR FOR METACRYL RESIN.
13. The method of claim 12,
Wherein the refractive index of the seed is smaller than the refractive index of the acrylic rubber core by 0.001 to 0.03 and the refractive index of the shell is larger by 0.001 to 0.03 than the refractive index of the shell.
14. The method of claim 13,
Wherein the refractive index of the acrylic rubber core is in the range of 1.4878 to 1.4889.
10 to 30% by weight of an impact modifier for methacrylic resin, and 70 to 90% by weight of a methacrylic resin,
Wherein said impact modifier for methacrylic resin satisfies the following condition: the refractive index of the acrylic rubber core in the impact modifier of claim 1 and the refractive index of the methacrylic resin within the range of 0.004 to 0.0002, And the refractive index of the shell is in the range of 1.48 to 1.49, and the difference in refractive index between the seed and the acrylic rubber core and the refractive index difference between the acrylic rubber core and the shell are in the range of 0.001 to 0.03, respectively.